Manchester United have been warned Juventus is "not a selling club" as they step up their pursuit of Paul Pogba.

The Reds are reputedly ready to pay at world record fee of £100m to bring the player back to Old Trafford following his departure to the Italian club in 2012.

But Juventus boss Massimiliano Allegri insists it is not a forgone conclusion that Pogba will leave the Serie A club and says he believes he could stay to win the league again and have another shot at the Champions League, labelling Juventus amongst "the top four European clubs".

"I am calm about the English rumours," Allegri said.

"Anyone who has the opportunity to leave Juventus has to consider things very carefully, because right now Juve are among the top four European clubs.

"This is not a selling club that just lets its players go. Pogba belongs to Juve and at the end of the day he too will want to win another Scudetto and hopefully the Champions League.

"We have grown in terms of appeal and awareness of our own capabilities. So far our market this summer has been eight out of 10, bringing in players of international pedigree like Medhi Benatia, Dani Alves and Miralem Pjanic."

Meanwhile, Mourinho has vowed he will give everything to deliver success to United's fans after kicking off his reign with a comfortable 2-0 friendly win over Wigan.

With the Euro 2016 contingent - including the likes of David de Gea, Wayne Rooney, Chris Smalling and Anthony Martial - resting, Mourinho's Red Devils bow was always likely to be a soft start, though second-half strikes from Will Keane and Andreas Pereira guaranteed a 2-0 win at the DW Stadium.

Everything about the 90 minutes was low key - from Mourinho's comfort-first leisure wear to his use of 22 different players - but the Portuguese admitted to being taken aback by the level of support he and his side received.

Around 7,000 United fans turned out for the gentle workout, unanimously roaring their support for a manager who is keen to pay them back after three relatively lean years under David Moyes and Louis van Gaal.

"I'm very happy, the result obviously is not the most important thing but it is always important," he said.

"Best of all was something that I never had before which was a friendly match, which I could call a training session against opposition, and I never saw something like this...so many supporters.

"They gave permanent support to the team, the manifestation of happiness about a few things they could see in the team, which was absolutely fantastic.

"If it is like this in a friendly match, like I said in my presentation, I will try to give them everything and I'm sure they will continue to give amazing support to the team."

Mourinho gave debuts to summer signings Eric Bailly and Henrikh Mkhitaryan, who arrived at a cost north of £55million, and saw plenty to please him. "Mkhitaryan is a top-class player and currently at the best stage for a footballer - 27/28 years old," said Mourinho.

"He is magnificent the way he thinks about football, he thinks very quickly and it's so sweet how he touches the ball. He can play in different positions behind the striker. He doesn't have the sharpness yet but his performance was very positive."

Bailly was given 82 minutes at the heart of defence, partnering Daley Blind in the first half and Phil Jones in the second.

United's preparations step up a notch on their forthcoming tour of China, where they face Dortmund, Galatasaray and neighbours Manchester City. And while Mourinho saw glimpses of encouragement he expects a lot more finesse as he continues his work with the squad.

"I'm happy with some principles of our play - offensively and defensively - that we worked on in training," he explained.

"This takes time but I could see different things; they started thinking football the way I think and that pleased me."